1. Field of the Invention
The present invention generally relates to jack side connectors and connector sets having the jack side connectors. More specifically, the present invention relates to a balanced transmission connector set and a jack side connector of the balanced transmission connector set.
2. Description of the Related Art
Conventionally, as a transmission method of transmitting data by a computer or between boards, unbalanced transmission or balanced transmission has been applied. In the unbalanced transmission, a signal is transmitted as a voltage relative to a ground electrical potential. In the balanced transmission, a pair of two equivalent signal lines is used and a signal is transmitted as an electrical potential difference between the signal lines. Since the balanced transmission has advantage in that, compared to the unbalanced transmission, noise may not have an influence, an area where the balanced transmission is used is expanding.
As a connector set for balanced transmission, a plug side connector and a jack side connector are used. In the plug side connector, plug side ground contacts formed of long plate shaped conductors and plug side signal contacts where conductors are provided at both end parts of long plate shaped insulators are mutually formed. The plug side contact is inserted in the jack side contact. The plug side signal contact is not limited to the above-mentioned example and may have a configuration where a pair of the conductors projects.
The jack side connector includes a jack side signal contact and a jack side ground contact which come in contact with the conductors so that conduction between the plug side and the jack side is formed.
In the plug side signal contact, a conductor provided at one side of the insulator transmits a + signal to the jack side signal contact. A conductor provided at another side of the insulator transmits a − signal to the jack side signal contact.
The plug side ground contact provides a ground electric potential at the plug side and the jack side. The plug side ground contact, together with the jack side ground contact, electromagnetically neighbor signal contacts.
In the meantime, it may be preferable that, in order to securely maintain a conducting state, a portion where the plug side contact and the jack side contact come in contact with each other be pressed and held in contact by a repulsive force of a contact members, a spring member, or the like.
For example, Japanese Laid-Open Patent Application Publication No. 2-216773 describes an invention of a connector for electric connecting, the connector having the above-mentioned feature.
In this connector for electric connecting, a donut-shaped slit is formed so as to extend in a longitudinal direction of a stick-shaped contact (corresponding to the plug side contact) to be inserted. This slit is sandwiched by a U-shaped contact (corresponding to the jack side contact). By a force received from the U-shaped contact, the stick-shaped contact is bent toward a center axial side of engagement. By the repulsive force of the stick-shaped contact, press contact of the contacts is strengthened.
However, if the connector for electric connecting described in Japanese Laid-Open Patent Application Publication No. 2-216773 is applied to, especially, the ground contact in the balanced transmission, it may be difficult to correspond to recent high frequency signal transmissions (electric power transmissions).
In the connector for electric connecting described in Japanese Laid-Open Patent Application Publication No. 2-216773, the stick shaped contact projects to a deeper side than a contact position of the stick-shaped contact and the U-shaped contact. Such a projecting part may be called a stub. Because of this, the signal (electrical current) to be transferred is returned from a head end so that noise may be generated.